Depth budget has become an important concept in binocular image creation. It may create a limit on the total binocular effect in a three dimensional image. This limit in practice is determined by considering many factors including the limits of the human visual system and the parameters of the image display device being used to present the image to the viewer. For stereoscopic images presented in an image plane the depth budget is often discussed in terms of depth behind and in-front of the image plane.
Techniques are known for controlling the perceived depth in stereoscopic images so that the total binocular effect remains within the depth budget by controlling the capture or synthesis of the image(s). FIG. 15 illustrates a reference U.S. Pat. No. 6,798,406, which generally provides a method for producing a stereoscopic image using at least one real or simulated camera wherein the depth of a scene is mapped to a predetermined depth budget in the perceived stereoscopic image. FIG. 21 illustrates a reference U.S. Patent Pub. No. US 2011/7,983,477, which generally discusses variable depth mapping from scene to perceived stereoscopic image. In addition a method such as that disclosed in U.S. Pat. No. 8,300,089 can also be used for variable depth mapping in the depth (Z) dimension.
The eye's binocular fixation may be determined using a range of eye tracking devices, either by tracking both eyes or by tracking a single eye and inferring the other from this information. One example of a binocular fixation tracking system is the Eyelink 1000, by Research Ltd., Mississauga, Ontario, Canada, which tracks both eyes at high speed.